Filter/emboli extractor for use in variable sized blood vessels

ABSTRACT

An extraction device for the removal of clots and foreign bodies from vasculature. The extractor device is connected to an elongate mandrel and is located within a longitudinally extending lumen defined by a catheter. A clot or foreign material extracted from a vessel by moving the extraction device and catheter proximally until the clot or foreign material does not perfuse a critical organ.

RELATED APPLICATIONS

This is based upon the provisional application Serial No. 60/140,131filed Jun. 21, 1999, entitled “FILTER/EMBOLI EXTRACTOR FOR USE INVARIABLE SIZED BLOOD VESSELS.”

BACKGROUND OF THE INVENTION

The present invention relates to medical devices that are useful intreating thromboembolic disorders and for removal of foreign bodies inthe vascular system.

Thromboembolic disorders, such as stroke, pulmonary embolism, peripheralthrombosis, atherosclerosis, and the like, affect many people. Thesedisorders are a major cause of morbidity and mortality in the UnitedStates.

Thromboembolic events are characterized by an occlusion of a bloodvessel. The occlusion is caused by a clot which is viscoelastic (jellylike) and is comprised of platelets, fibrinogen and other clottingproteins.

When an artery is occluded by a clot, tissue ischemia (lack of oxygenand nutrients) develops. The ischemia will progress to tissue infarction(cell death) if the occlusion persists. Infarction does not develop oris greatly limited if the flow of blood is reestablished rapidly.Failure to reestablish blood-flow can lead to the loss of limb, anginapectoris, myocardial infarction, stroke or even death.

Occlusion of the venous circulation by thrombi leads to blood stasiswhich can cause numerous problems. The majority of pulmonary embolismsare caused by emboli that originate in the peripheral venous system.Reestablishing blood flow and removal of the thrombus is highlydesirable.

There are many existing techniques employed to reestablish blood flow inan occluded vessel. One common surgical technique, an embolectomy,involves incising a blood vessel and introducing a balloon-tipped device(such as the Fogarty catheter) to the location of the occlusion. Theballoon is then inflated at a point beyond the clot and used totranslate the obstructing material back to the point of incision. Theobstructing material is then removed by the surgeon. While such surgicaltechniques have been useful, exposing a patient to surgery may betraumatic and best avoided when possible. Additionally, the use of aFogarty catheter maybe problematic due to the possible risk of damagingthe interior lining of the vessel as the catheter is being withdrawn.

Percutaneous methods are also utilized for reestablishing blood flow. Acommon percutaneous technique is referred to as balloon angioplastywhere a balloon-tipped catheter is introduced to a blood vessel,typically through an introducing catheter. The balloon-tipped catheteris then advanced to the point of the occlusion and inflated in order todilate the stenosis. Balloon angioplasty is appropriate for treatingvessel stenosis but is generally not effective for treating acutethromboembolisms.

Another percutaneous technique is to place a microcatheter near the clotand infuse streptokinase, urokinase or other thrombolytic agents todissolve the clot. Unfortunately, thrombolysis typically takes hours todays to be successful. Additionally, thrombolytic agents can causehemorrhage and in many patients the agents cannot be used at all.

Another problematic area is the removal of foreign bodies. Foreignbodies introduced into the circulation can be fragments of catheters,pace-maker electrodes, guide wires, and erroneously placed embolicmaterial such as thrombogenic coils. There exists retrieval devices forthe removal of foreign bodies, certain of such devices form a loop thatcan ensnare the foreign material by decreasing the size of the diameterof the loop around the foreign body. The use of such removal devices canbe difficult and sometimes unsuccessful.

Various thrombectomy and foreign matter removal devices have beendisclosed in the art. However, such devices have been found to havestructures which are either highly complex or lacking in sufficientretaining structure. Disadvantages associated with the devices havinghighly complex structure include difficulty in manufacturability as wellas use in conjunction with microcatheter. Other less complex devicestend to pull through clots due to in part to the lack of experience inusing the same or are otherwise inadequate in capturing clots or foreignbodies.

Moreover, systems heretofore disclosed in the art are generally limitedby size compatibility and the increase in vessel size as the emboli isdrawn out in the distal vascular occlusion location to a more proximallocation near the heart. If the embolectomy device is too large for thevessel it will not deploy correctly to capture the clot or foreign bodyand if too small in diameter, it cannot capture clots or foreign bodiesacross the entire cross section of the blood vessel. Additionally, ifthe embolectomy device is too small in retaining volume, as the deviceis retracted, the excess material being removed can spill out and becarried by flow back to occlude another distal vessel.

Thus, there exists a need for an extraction device that can be easilydeployed into the circulatory system for the effective removal of clotsand foreign bodies. There is also a need for a device which could beused as a temporary arterial or venous filter to capture and removethromboemboli formed during endovascular procedures.

SUMMARY OF THE INVENTION

The present invention is directed to devices that are useful in removingclots and foreign bodies from vessels. Various embodiments and method ofuse are disclosed for the effective removal of clots or foreign bodies.It is contemplated that the present invention may be used in allvasculature including the neurovasculature.

In one aspect of the invention, an elongate generally linear wire isprovided for the removal of certain types of undesirable matter found ina blood vessel. The elongate generally linear wire is placed within theundesirable matter and rotated to thereby catch the matter and wind itabout the wire. Withdrawing the wire within a receiving tube or directlythrough the vessel operates to extract the undesirable matter from thepatient's vasculature.

In another aspect of the invention, a staged filter/emboli extractor isprovided to remove clots or foreign material from a vessel. In oneembodiment, a plurality of spaced-apart radially extending structuresare configured on an elongate wire or tubular mandrel proximal a distalend of the mandrel. The radially extending structures are characterizedby increasing in size from the most proximal structure to the mostdistal structure. In a presently preferred embodiment, each of theradially extending structures are in the form of a plurality of loops orpetals arranged in an annular radial array about the circumference ofthe mandrel. In an alternative embodiment, each of the plurality ofloops or petals originate from a common side of the mandrel and can beconcentrically arranged.

In yet a further aspect of the invention, a knitted or mesh structure isprovided for the removal of clots or foreign material from a bloodvessel. The knitted or mesh structure is configured near the distal endportion of an elongate wire or tubular mandrel. In one presentlycontemplated embodiment, the knitted or mesh structure is affixed in aconventional manner to the distal end of the mandrel. In anotherpresently contemplated embodiment, the knitted or mesh structuresurrounds a distal portion of the mandrel and may additionally embodystructure enabling one end of the knitted or meshed structure to betranslated longitudinally with respect to its other end which is heldfixed. The knitted or mesh structures disclosed are furthercharacterized by having open or closed ends or a basket-likeconfiguration.

The invention also includes an elongate tubular delivery catheter withat least one lumen for receiving an extractor device and for retainingthe distal portion thereof in a reduced profile. The delivery cathetermay be used in conjunction with an elongate insertion catheter that isconfigured to be introduced into a large vessel and advanced within apatient's vasculature.

Generally, the clot is extracted from a vessel by capturing the same andwithdrawing the clot or foreign material proximally until it can beremoved or released into a different vessel that does not perfuse acritical organ. The structure disclosed can also be used as a temporaryarterial or venous filter to capture and remove thromboemboli formedduring endovascular procedures. By removing the device from the body,the clot or foreign material is also removed.

Other features and advantages of the present invention will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings, which illustrate, by way of example, theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a schematic illustration depicting an occluded vessel with acatheter shown partially in cross-section and a first embodiment of anextraction device of the present invention;

FIG. 1b is a schematic illustration depicting the extraction device ofFIG. 1a inserted through an occlusion;

FIG. 1c is a schematic illustration depicting the extraction device ofFIG. 1b withdrawing a clot from a vessel;

FIG. 2a is a schematic illustration depicting the extraction device ofFIG. 1a encountering a clot in another area of vasculature;

FIG. 2b is a schematic illustration depicting the extraction device ofFIG. 2a withdrawing the clot from a vessel;

FIG. 3a is a schematic illustration depicting an occluded vessel with acatheter and a second embodiment of extraction device of the presentinvention;

FIG. 3b is a schematic illustration depicting the catheter of FIG. 3ashown in partial cross-section and being inserted through an occlusion;

FIG. 3c is a schematic illustration depicting the extraction device of 3a advanced longitudinally with respect to the catheter;

FIG. 3d is a schematic illustration depicting withdrawing the catheterand extraction device to ensnare a clot within an occluded vessel;

FIG. 4 is a schematic illustration depicting the second embodiment ofthe extraction device being deployed within an occlusion;

FIG. 5a is a schematic illustration depicting a first step inmanufacturing the extraction device of FIG. 4;

FIG. 5b is a schematic illustration depicting a second step ofmanufacturing the extraction device of FIG. 4;

FIG. 6 depicts a third embodiment of the extraction device of thepresent invention;

FIG. 7 depicts a fourth embodiment of the extraction device of thepresent invention;

FIG. 8 depicts a fifth embodiment of the extraction device of thepresent invention;

FIG. 9 depicts a sixth embodiment of the extraction device of thepresent invention;

FIG. 10 is a schematic illustration depicting a seventh embodiment ofthe extraction device of the present invention;

FIG. 11 is a schematic illustration depicting an eighth embodiment ofthe extraction device of the present invention;

FIG. 12 is a schematic illustration depicting a ninth embodiment of theextraction device of the present invention;

FIG. 13 is a schematic illustration depicting a tenth embodiment of theextraction device of the present invention; and

FIG. 14 is a plan view of the present invention being deployed within aninsertion catheter with a side suction port.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is useful for the removal of clots or foreignmaterial from vasculature. The present invention is intended to be usedin various sized vessels and in vessels having varying degrees oftortuosity. Of particular significance is the contemplated use of thepreferred embodiment in the highly tortuous neurovasculature. Moreover,the disclosed extraction devices are characterized by having structurethat is useful as filter devices.

Referring to FIGS. 1a-c, there is shown a first embodiment of thepresent invention being used to extract a clot or foreign material 20from a vessel 22. In the presently preferred first embodiment, anelongate wire 24 embodies an extraction device. The elongate wire 24 isconfigured longitudinally within a lumen 26 defined by an elongatetubular delivery catheter 28.

The elongate wire 24 may comprise a conventional guidewire or other wirestructure having similar properties. One material of choice may beNitinol. Its exterior may be scored or include other surfaceirregularities (not shown) for the purpose of enhancing engagement withcertain types of clots or foreign bodies found in a patient'svasculature. Its outer diameter is such that it can easily slide withinthe lumen 26 of the catheter 28. Generally, the elongate wire 24 has alength greater than that of the catheter 28 so that its proximal end canbe grasped by an operator and so that the elongate wire can be advancedand withdrawn independently of the catheter 28.

The delivery catheter 28 can be any commercially available catheter thatis made out of any appropriate biologically compatible material.Typically, the catheter will have a single lumen 26 as constructed outof a flexible elastomeric material such as silicone, rubber,polyvinylchloride, polyeurothanes, polyesters, polytetrafluoroethyleneand the like. The catheter has to be flexible enough and long enough tonavigate through blood vessels to the occluded vessel where clots orother foreign bodies 20 are located. Typically the catheter will rangein length from about 20 to about 175 centimeters.

The outer diameter of the catheter can also vary. Typically, the outerdiameter will range from about 2 to about 10 F (1 F equals 0.013 inch).The inner diameter will range from about 1 to about 9 F.

In use, the elongate wire 24 and catheter 28 are inserted into apatient's vasculature using conventional techniques, using fluoroscopyor other conventional means. The elongate wire 24 and catheter 28 areadvanced within a patient's vasculature 22 to the location proximal tothe clot or foreign body 20 to be extracted. The elongate wire 24 isthen advanced independently of the delivery catheter 28 and across theclot or foreign material 20. Next, the elongate wire 24 is rotated tothereby catch the clot or foreign material 20 and wind it about theelongate wire 24. Thereafter, the elongate wire 24 with the clot orforeign material adhered thereto is withdrawn within the deliverycatheter 28 and both the elongate wire and-delivery catheter are removedfrom the patient's vasculature. Alternatively, the elongate wire 24 isdirectly removed from the patient's vasculature without firstwithdrawing it within the delivery catheter 28.

It has been observed that the elongate wire 24 is particularly useful incapturing fibrin clots. As shown in FIGS. 2a-b, the elongate wire 24 isuseful even where there is just a small amount of fibrin tendril 30 of aclot 31 extending from a branch 32 into a parent lumen 34. In such asituation, the elongate wire 24 is placed adjacent the fibrin tendril 30and is rotated to first catch the fibrin 30 and then wind the clot 31about the elongate wire 24. The clot 31 can then be removed from thepatient's vasculature by withdrawing the elongate wire 24.

A second preferred embodiment of the present invention is shown in FIGS.3a-d. The second embodiment is a staged filter/emboli extractor 40 thatincludes a plurality of spaced-apart radially extending structures 42configured on a mandrel 44. The radially extending structure 42 eachembody a plurality of loops or petals 46 arranged in an angular radialarray about the circumference of the mandrel 44. As shown in thebreak-out illustration included in FIG. 3a which depicts an end view ofone radially extending structure 42, it is contemplated that each loopor petal 46 be configured to overlay at least a portion of the nextadjacent petal in an over-under pattern such that each loop/petal 46supports another loop/petal 46. It is also contemplated that eachloop/petal can overlay/underlay two or more petals in a supportingfashion.

The number of petals or loops 46 of a radially extending structure 42can range from 3-8 or more depending on the size of the petal or loop.The petal or loop itself can have a circular or generally ovalconfiguration with its opening defining a space having a cross-sectionranging from 0.050 inches or smaller to 2.125 inches and larger across.The wire used to form the loops 46 can be made of NiTi wire having adiameter ranging from 0.002-0.0055 inches or more.

In a preferred embodiment of the staged filter/emboli extractor 40,there are three spaced-apart radially extending structures formed on themandrel 44. The petals/loops are configured to project from the mandrel44 at a distally directed angle and are characterized by increasing insize or cross-sectional profile as one moves distally along the mandrel44. However, it is to be recognized that as few as one and as many aseight or more radially extending structures can be configured on themandrel 44. Moreover, depending on the application, the petals canproject at a proximally directed angle and can either decrease in sizeor cross-sectional profile or vary as one moves distally along themandrel 44.

The mandrel 44 has to be relatively stiff to support the stagedfilter/emboli extractor 40. In the preferred embodiment, the insertionmandrel is made out of stainless steel and is a solid wire from about0.005 to about 0.038 inches in diameter. Other materials can be usedsuch as hard plastic, Nitinol, and the like to make the insertionmandrel. The insertion mandrel is 10-20 centimeters longer than thecatheter such that the operator of the device (typically a physician)can control the insertion mandrel 44 by gripping the proximal end whichextends from the proximal end of the delivery catheter 28 with which itis used.

With reference to FIGS. 5a-b, in order to manufacture the stagedfilter/emboli extractor 40, the wire defining the loops/petals is formedinto a hoop 52 with its lead ends 54 inserted into an hypotube 56. Thehoop portion 52 is placed over a petal mandrel 58 having an outerdiameter of a particular dimension. Different sized petal mandrels areused for forming different sized hoops. The hypotube 56 is slid towardsthe petal mandrel 58 in order to form an appropriate sized hoop 52.Next, the hoop 52 is angled to a desirable degree with respect to thepetal mandrel 58. Angles of 30° degrees or less and 80° degrees or moreare contemplated. Thereafter, the wire 50 is heated for about thirtyseconds with a heat gun to approximately 1100° degrees Fahrenheit forthe purpose of annealing the wire 50 and setting the angle of the wire50 with respect to the petal mandrel 58. The hypotube 56 is removed andthe lead ends 54 of the wire are cut to a desired length. A desirednumber of loops/petals 46 are formed in this matter.

Next, a coil retainer 60 is slipped over a ceramic (non-solderable) rod62 projecting from a support 64. The remaining lead ends 54 of theloops/petals 46 are then placed between the ceramic rod 62 and coilretainer 60. Thereafter, the remaining lead ends are soldered to theretainer 60. The soldered assembly is removed from the ceramic rod 62and is ready to be affixed to the mandrel 44 in any conventional mannerincluding soldering or using adhesives.

Multiple loops/petals 46 can alternatively be simultaneouslymanufactured using a similar procedure. Generally, manufacturing theloops/petals 46 can be accomplished by looping a single wire 50 about acombination of rods that form the loops/petals as well as an auxiliaryrod from which the loops/petals originate. Thereafter, the multipleloops can be affixed directly to a mandrel 44 or first cut and thenaffixed thereto.

In operation (see FIGS. 3a-d), the staged filter/emboli extractor 40 isplaced longitudinally within a lumen 26 defined by a catheter 28. It isto be recognized that when the staged filter/emboli extractor 40 isplaced within the catheter 28, the individual loops/petals 46 are heldin a compressed configuration. That is, the radially projectingstructures 42 define a smaller cross-sectional profile when containedwithin the delivery catheter 28, the degree of reduction in profilebeing controlled by the inner diameter of the delivery catheter.

The extractor 40 and catheter 28 are then inserted into a patient'svasculature using conventional techniques. Using fluoroscopy or otherconventional means, the extractor 40 and catheter 28 are advanced withina patient's vasculature 22 to a location proximal to the clot or foreignbody 20 to be extracted. The delivery catheter 28 with extractor 40contained therein is then advanced so that the delivery catheter 28traverses the clot or foreign body 20 to be extracted. The stagedfilter/emboli retractor 40 is then advanced independently of thedelivery catheter 28 so that the radially projecting structures 42 arepositioned distally with respect to the clot or foreign body 20.

When the extractor 40 is so positioned, the radially projectingstructures 42 are permitted to spring outwardly and assume anuncompressed or less compressed configuration, the angle of theloops/petals 46 with respect to the mandrel 44 being defined during themanufacturing process.

Subsequently, the staged filter/emboli extractor 40 is withdrawn intoengagement with the clot or foreign material 20 for the purpose ofcapturing the same. While withdrawing the extractor 40 rotationalmovement may be applied for the purpose of enhancing the ability of theextractor 40 to capture the clot or foreign material 20. As theextractor and delivery catheter 28 are continued to be withdrawnproximally, the entirety of the clot or foreign material 20 is removedfrom the vessel. It is contemplated that the radially projectingstructures 42 are relied upon to extract the clot or foreign body 20without the interaction of the delivery catheter 28. Alternatively, itis also contemplated that the extractor be withdrawn within the deliverycatheter once it has engaged and captured the clot or foreign material20.

It is to be recognized that use of combined staged variable sizedelements in a single device such as the staged filter/emboli extractorhas a number of advantages. That is, when deployed in a distal anatomy,distal to an emboli for an example, the correct size radially extendingstructure 42 engages the emboli first. As the emboli is retracted tolarger vessels, if the first radially extending structure 42 is toosmall in diameter or volume, any “spilled” material can be caught by asubsequent radially extending structure 42. Moreover, employing multipleradially extending structures 42 on the extractor 40 inherently has theadvantage of engaging a clot or foreign material 20 a multiple of times,thereby assuring that any undesirable matter left behind after a firstpass will be collected during subsequent passes.

With reference to FIG. 4, it is also to be recognized that the stagedfilter/emboli extractor 40 can also be deployed directly within a clotor foreign material 20 for the purpose of removing the undesirablematter from the patient's vasculature. Thus, rather than deploying theextractor 40 distal to the undesirable matter and withdrawing theextractor 40 through the same, it is possible to also release theextractor 40 directly within the clot or foreign material 20. Inpractice, it may also be beneficial to deploy the extractor 40 so thatthe appropriate sized radially extending structure 42 first engages theclot or foreign matter 20. Once the extractor 40 has engaged andcaptured the undesirable matter, the extractor. 40 can be withdrawnproximally to remove such matter from the patient's vasculature.

Moreover, in certain situations it might be beneficial to employ amandrel 44 which further includes a lumen (not shown) which extendssubstantially the length of the mandrel 44. Such a mandrel 44 could thenbe threaded over an appropriate sized guidewire in order to facilitatethe advancement of the extractor 40 within a patient's vasculature.

Various other embodiments of extractors may be useful in removingundesirable material from blood vessels. Such other embodiments ofextractors can be deployed distally with respect of the undesirablematerial and withdrawn or they can be directly deployed within suchundesirable material and thereafter removed from the blood vessel.Moreover, other such embodiments of extractors may be used inconjunction with a delivery catheter 28 which operates to deliver theextractor to the repair site as well as releasably hold the extractor ina compressed configuration.

As shown in FIG. 6, a third embodiment of an extractor 70 includes aplurality of spaced-apart asymmetric radially extending structures 72originating from one side of the mandrel 74. By employing asymmetricradially extending structures, it maybe easier to manufacture the same.Additionally, such asymmetric radially extending structures may becompressed into a catheter lumen more easily and may more effectivelyhandle corners or tortuous vasculature. As with the second embodiment ofthe present invention, a mandrel 74 can embody a solid or tubularstructure. The asymmetric radially extending structures 72 can numberfrom 1 to 8 or more and can each include a plurality of concentricallyarranged loops or petals 76. The concentrically arranged loops or petals76 of a particular asymmetric radially extending structure 72 can numberfrom 2 to 5 or more depending on the application and innermost loop 78can be a first cross-sectional size with subsequent loops concentricallyarranged thereabout having ever increasing cross-sectional profiles.

In certain circumstances, it may be desirable to have the asymmetricradially extending structure 72 increasing in size as one moves distallyalong the mandrel 74. However, in other instances, the asymmetricradially extending structures 72 can decrease or otherwise vary inprofile as one moves distally along the mandrel 74. Moreover, as withthe second embodiment of the present invention, the asymmetric radiallyextending structures 72 are contemplated to angle distally with respectto the mandrel but can also be angled proximally. The same materials andsimilar manufacturing steps can be employed to produce the extractor 70.Furthermore, as stated, the extractor 70 can be used in conjunction withthe delivery catheter 28 according to the method set forth above inconnection with the prior embodiments of the present invention.

Referring to FIGS. 7-13, extractors employing knitted or mesh structuresare shown. Such extractors can also be used in conjunction with adelivery catheter according to the methods set forth above inconjunction with the prior embodiments of the present invention. Inparticular, such extractors may be used in connection with a deliverycatheter and can be rotated, and withdrawn to capture undesirablematerial.

As shown in FIG. 7, a fourth embodiment of the present inventionembodies a knitted or mesh, hollow basket-like extractor 80 whichincludes a basket 82 attached to a mandrel 84. The mandrel 84 can be asolid or tubular structure. The basket 82 includes a mesh or knittedportion 86 connected by conventional means such as welding via aplurality of proximally extending arms 88 to the distal end of themandrel 84. The knitted or mesh portion 86 may form a cone-likeconfiguration with its most distal end 89 defining the apex of the cone.It is to be recognized, however, that other basket configurations mayalso be employed. The basket-like extractor 80 is characterized byproviding structure which may be particularly useful in collectingmatter in its hollow interior as blood flows therethrough.

As shown in FIG. 8, a fifth embodiment in the present invention includesa hollow knitted or mesh extractor 90 attached to a distal end of asolid or tubular mandrel 92. In this embodiment, the knitted or meshportion has a cone-like proximal portion 94 that is welded or otherwiseaffixed to the distal end of the mandrel 92 as well as a generallycylindrical distal portion 96 which extends integrally from the proximalportion 94. The distal most end 98 of the knitted or mesh structureterminates at a generally right angle to a longitudinal axis of theknitted or mesh portion and further defines an opening to the hollowinterior of the device. This device may provide a relatively largercross-section for blood to flow through its distal end while the devicecontinues to trap undesirable material in a blood vessel or compress thesame against the vessel wall.

A sixth embodiment of the present invention is shown in FIG. 9. In thispresently preferred embodiment, a knitted or mesh structure 100 isattached by conventional means such as welding to a distal end of asolid or tubular mandrel 102. The knitted or mesh structure 100 has ahollow interior and further includes a proximally directed cone-likeportion 104 attached to the mandrel 102, a generally cylindricalmid-section 106 extending integrally from the proximal portion 104, anda distally directed cone-like portion 108 extending integrally from thegenerally cylindrical mid-section 106. Such a device may provide theadvantage of improved deployability in that it might be more easilyejected from a delivery catheter and permitted to more fully expand.

A seventh embodiment of the present invention is shown in FIG. 10. Inthis contemplated embodiment, a knitted or mesh cup-like structure 110is affixed to a solid or tubular mandrel 112 proximal to a distal end ofthe mandrel 112. The cup-like structure 110 includes a proximallydirected, generally circular opening 114 which provides access to aninterior of the hollow device. The cup-like structure 110 also includesa distal end portion 116 that narrows in a cone-like fashion, the distalmost part 118 of which is attached to the mandrel 112. In certaincircumstances, it may be desirable to employ a collar (not shown) to aidin so affixing the device to the mandrel 112.

As shown in FIG. 11, an eighth embodiment of the present inventionembodies a basket-like extractor 120 which includes a plurality of arms122, one end of each of which being affixed to a solid or tubularmandrel 124, the other end of each of which being attached to or loopedabout a hollow basket 126. The basket 126 includes a proximal generallycylindrical portion 127 and a distal portion 128 integrally extendedtherefrom in a cone-like matter. The very distal end portion of thedistal portion 128 surrounds the mandrel 124 such that it can slideindependently over the mandrel 124.

A ninth embodiment in the present invention is depicted in FIG. 12. Inthis embodiment, the extractor includes a hollow knitted or meshstructure 132 that has a generally cylindrical mid-section 133, andproximal 134 and distal 135 portions integrally extending from themid-section 133 and which narrow in a cone-like manner therefrom. Theproximal portion 134 is welded or otherwise affixed to a solid ortubular mandrel 136. The distal portion 135 surrounds the mandrel 136 ina manner such that the distal portion can slide independently of themandrel 136. A collar 138 can be employed to aid in affixing theproximal end 134 to the mandrel 136.

As shown in FIG. 13, a tenth embodiment of the present inventionincludes a braided or knitted balloon 140. A distal end 142 of theballoon 140 is attached to a distal end of a central mandrel 144,whereas its proximal end is attached to a distal end 145 of an elongateouter tube assembly 146. In the presently preferred embodiment, themandrel 144 is configured longitudinally within the outer tube assembly146. It is also contemplated that the mandrel 144 have a length greaterthan the outer tube 146 so that an operator can grasp both the mandrel144 and outer tube assembly 146 independently. Through manipulation ofthe outer tube assembly 146 independently of the mandrel 144, thebraided balloon 140 can be caused to expand or contract radially.

In order to manufacture the knitted or braided structure of theaforementioned extractors, either a plurality of wires or a single wirecan be used. It is contemplated that the wires be comprised of Nitinolor other materials having similar properties. In the event a pluralityof wires are used to form the knitted or mesh structures, fourspaced-apart wires for example, may be wrapped in helical fashion in aclockwise direction about a mandrel (not shown) having a desiredprofile. The forming mandrel itself is used to define the profile of theresulting extractor configuration. An additional like number of spacedwires could simultaneously be helically wrapped in a counter clockwisedirection in an over/under pattern with the wires being wrapped aboutthe mandrel in a clockwise direction to thereby form the desired knittedor mesh configuration. Alternatively, a single wire can be wrapped in ahelical fashion about a mandrel (not shown) that includes a plurality ofpegs extending from the ends of the mandrel, the pegs being employed toaid in reversing the direction of winding. An over/under pattern ofwinding may also be employed to produce the desired knitted or meshstructures. A particular advantage of using one wire to form the knittedor mesh structure is that such a resultant structure is characterized byhaving atraumatic ends, a high expansion ratio and high flexibility.

The size of the filament or wire employed to construct the braid as wellas angles between the filaments can be selected for the particularapplication. Moreover, the radial and longitudinal dimensions of thebraid structure can likewise be varied for a particular application.However, the same effective range of dimensions contemplated for thesecond and third embodiments described above would be acceptable for theknitted or braided embodiments.

The extractors/filters and delivery catheter systems heretoforedescribed are also contemplated to be used with an insertion catheter. Aparticularly useful insertion catheter is illustrated in FIG. 14 (theextractor being schematically represented at a distal end of theassembly). The insertion catheter 150 is hollow with a single lumen andhas a Y junction towards its proximal end. The insertion catheter is astandard commercially available catheter. The insertion catheter has twoports, 152 and 154. Port 152 is in straight communication with thelongitudinal axis of the insertion catheter 150 and is useful for theinsertion of the delivery catheter 28 and an extractor of the presentinvention and mandrels associated therewith. The other port, which isangled away from the longitudinal axis of the insertion catheter, is forthe attachment to a suction line from a vacuum source. Located at thedistal end 156 of the insertion catheter is a marker band 158 that canbe located via radiographic means while the insertion catheter is beingused.

In practice, the insertion catheter 150 is inserted through a largevessel and through the vascular system to a position near a clot orforeign body in an occluded artery under fluoroscopic guidance. Thedelivery catheter 28 is then inserted through port 152 and through theinsertion catheter 150 such that the distal end of the catheter 28 haspassed the distal end 156 of the insertion catheter 150. The deliverycatheter 28 or extractor is then translated across the clot or foreignbody (not shown). The mandrel is then translated proximally to ensnarethe foreign body or clot which is then translated toward the distal end156 of the insertion catheter 150. Once the clot or foreign body is atthe distal end 156, suction is applied via port 154 to suck part of thesame into the distal end 156. Thereafter, the insertion catheter 150,the delivery catheter 28, the extractor and undesirable material areremoved from the patient.

It is also contemplated that the present invention can be used as afilter in a blood vessel. In such a situation, the above-describedextractors are deployed within a blood vessel and held stationary for aperiod of time sufficient for the extractor to remove unwanted materialfrom a patient's bloodstream.

Thus, an extractor system is disclosed which allows for the removal ofthromboembolic material and foreign bodies from a blood vessel. Whileseveral particular forms and applications of the invention have beenillustrated and described, it will be apparent to those skilled in theart that many more modifications are possible without departing from thespirit and scope of the invention. The invention, therefore, is not tobe restricted except in the spirit of claims appended hereto.

I claim:
 1. A device for removing unwanted material from vasculature,comprising: an elongate wire having a distal end; and at least tworadially extending structures spaced apart longitudinally along theelongate wire proximate the distal end, at least one radially extendingstructure including a loop having a rounded atraumatic end, the looporiginating and terminating at a substantially common longitudinalposition on the elongate wire.
 2. The device of claim 1, wherein theradially extending structures have a different outside radius.
 3. Thedevice of claim 2, wherein a distal most radially extending structurehas a larger outside radius than the adjacent radially extendingstructure.
 4. The device of claim 1, wherein each radially extendingstructure is affixed to the elongate wire such that rotation of the wireentangles the radially extending structures in the unwanted material. 5.The device of claim 1, wherein each radially extending structurecomprises a plurality of loops arranged in an annular radial array aboutthe circumference of the wire.
 6. The device of claim 1, wherein certainof the radially extending structures overlay an adjacent radiallyextending structure.
 7. The device of claim 1, wherein the radiallyextending structures extend transversely to the elongate wire.
 8. Thedevice of claim 1, wherein the elongate wire has a length sufficient toextend from within a patient's vasculature to outside the patient'svasculature.
 9. The device of claim 1, wherein the device is configuredto be used with a delivery catheter.
 10. The device of claim 9, whereinthe delivery catheter is configured to retain the device in a radiallycompressed configuration.